Hydraulic fracturing

ABSTRACT

An improvement over known hydraulic fracturing fluids. Boundary layer kinetic mixing material is added to components of fracturing fluid wherein kinetic mixing material is a plurality of particles wherein at least 25% of particles are several types, i.e., having surface characteristics of thin walls, three dimensional wedge-like sharp blades, points, jagged bladelike surfaces, thin blade surfaces, three-dimensional blade shapes that may have shapes similar to a “Y”, “V” or “X” shape or other geometric shape, slightly curved thin walls having a shape similar to an egg shell shape, crushed hollow spheres, sharp bladelike features, 90° corners that are well defined, conglomerated protruding arms in various shapes, such as cylinders, rectangles, Y-shaped particles, X-shaped particles, octagons, pentagon, triangles, and diamonds. The resulting fluid exhibits improved dispersion of additives as well providing stabilization to a hydraulic fracture by reducing incidents of proppant grain column collapse and by reducing proppant flow back.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Utility patent applicationSer. No. 13/167,683, filed Jun. 23, 2011, titled, “HYDRAULICFRACTURING”, which claims priority to U.S. Provisional PatentApplication No. 61/357,586, filed Jun. 23, 2010, titled “HYDRAULICFRACTURING” the contents of each of which are hereby incorporated byreference. This application additionally claims the priority of U.S.patent application Ser. No. 12/572,942, filed Oct. 2, 2009, titled,“STRUCTURALLY ENHANCED PLASTICS WITH FILLER REINFORCEMENTS”, whichclaims priority to U.S. patent application Ser. No. 12/412,357, entitled“STRUCTURALLY ENHANCED PLASTICS WITH FILLER REINFORCEMENTS”, filed Mar.26, 2009, which claims the priority of U.S. Provisional PatentApplication No. 61/070,876 entitled “STRUCTURALLY ENHANCED POLYMER WITHFILLER REINFORCEMENTS”, filed Mar. 26, 2008, the contents of each ofwhich are hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to improvements in fluids used in the oil and gasrecovery process known as hydraulic fracturing. More particularly, theinvention relates to an improvement of hydraulic fracturing performancedown a well bore and into a fracture. More particularly, the inventionprovides stabilization to a hydraulic fracture by reducing incidents ofcollapse of proppant grain columns and by reducing proppant flow back.

BACKGROUND OF THE INVENTION

Much of the earth's remaining natural gas and oil is located in rockshale and rock formations at depths varying from 500-20,000 feet belowthe surface. Many of the naturally occurring formations suffer from lowporosity and permeability, thereby restricting natural gas and/or oil toflow into a well bore where the gas and/or oil can be recovered.

Hydraulic fracturing is a process that creates fractures in lowporosity, low permeability rocks of geological formations. A hydraulicfracture may be formed by pumping a fracturing fluid mixture into a wellbore at a rate sufficient to increase pressure down-hole to a value inexcess of the fracture gradient of the formation rock. The pressurecauses the formation to crack or fracture, which allows the fracturingmixture to enter and extend the crack further into the formation.

To keep a fracture open after the pumping process stops, the fracturingfluid mixture contains a solid, called a proppant, that remains in thenew fracture and keeps the fracture open. Various types of proppant maybe used depending on the permeability or grain strength needed. Acompleted fracture provides a conductive path connecting a large area ofthe reservoir to the well, thereby increasing the area from which oil,natural gas and liquids can be recovered from the targeted formation.

Propped hydraulic fracture stimulation is widely used to improve wellproductivity from tight, otherwise noncommercial reservoirs. Other areasof application include sand control in weakly consolidated reservoirs,gas condensate fields, and high permeability reservoirs that showsignificant permeability anisotropy.

An important consideration in the practice of hydraulic fracturing is“proppant flow-back”, i.e., the production of proppant back to thesurface. Proppant flow-back can lead to damaged equipment and downtime,which necessitates costly and manpower intensive surface handlingprocedures. Proppant flow-back also presents a problem of proppantdisposal. In some cases, a well can be prematurely abandoned if costs toreturn the well to production are excessive. Proppant flow-back,although not desirable, can be tolerated in certain operationalenvironments. However, proppant flow-back from a fracture during theproduction phase is problematic. In practice, 20% to 50% of the originalproppant pumped into a formation may be produced back.

An integral part of a hydraulic fracturing process is the introductionof proppant particles of various sizes into a fracture to hold thefractures open. Examples of proppants include structural materials suchas sand, man-made ceramics, walnut shells and even polymer beads.Additionally, resin coated proppants have been used in an effort toreduce proppant flow-back. The resin coated proppant approach of gluingthe sand together at the interface was an excellent starting point toreduce flow-back but mechanical cycling tends to crack the bonds thatinterconnect the proppant grains, thereby creating failure.

Studies have been undertaken to determine the mechanisms of flow-back.Laboratory work and theoretical simulations of several thousandindividual proppant grains have shown that flow-back of plain proppantis critically dependent upon the ratio of mean grain diameter tofracture width. This dependence can be visualized as larger “columns” ofproppants that have a greater tendency to buckle under loading. As aresult of closure stress and inter-particle friction, a geometricallyirregular arch of proppant grains is formed behind the fracture mouth.The buckled columns of proppant in front of the arch carry virtually noload. Therefore, small levels of proppant are initially transported tothe well-bore even at low fluid flow rates. The loaded arch is stableuntil a sufficient fluid drag force is reached that is able to collapsethe arch. A collapsing arch results in further proppant flow-back. Anarch is a curved structure spanning an opening, serving to support aload by resolving the normal stress into lateral stress. For an arch toform, closure stress is required to generate a reaction force with theface of the fracture. The resolution of the forces in an archnecessarily sets up a pattern of shearing stresses within the material.At high closure stress these shear forces can become excessive and leadto pack failure.

Modes of proppant pack failure leading to proppant flow back are thoughtto be caused by arch destabilization due to excessive hydraulic and/orgravitational forces. Other modes of proppant pack failure are believedto include a fracture closure stress that is too low, proppant packshear failure caused by too high fracture closure stress, as well aspossible proppant crushing at high closure stress.

Critical parameters determining flow-back of plain proppants includefracture closure stress, both stabilizing and destabilizing. Othercritical parameters include hydrodynamic force imposed from fluidproduction, which is destabilizing as the fluid flow tends to buckleproppant columns at the fracture mouth. Other critical parametersinclude the fracture width, which affects arch geometry and the transferof friction and stress forces acting on proppants at a free face. Thus,for the same gradient, larger proppants will experience a greaterdestabilizing force. Similarly, at the fracture face the larger theproppant the fewer proppants per unit area are available to resist theapplied closure stress and the larger the normal stress at the proppantcontact.

A typical fracturing fluid mixture is made up of carrier fluid,additives and proppants. Typically, the carrier fluid and proppantcomprise 99% of the mixture with less than 1% additives.

There are five types of carrier fluids normally used in the process. Thefive types are, 1) Water: which is typically un-gelled freshwater orformations of brine; 2) Cross-linked water-based fluids, which aregelled with polymers that employ a cross-linking agent, such as ametallic ion to bond the polymer molecules together for increasing fluidviscosity; 3) Oil-based fluids, which include gelled oils, diesel orlease crude; 4) Oil-in-water emulsions, which are external phase gelledwater, internal phase gelled diesel, lease crude or condensates; and 5)Foam, which is a mixture of gas, e.g., nitrogen or carbon dioxide,gelled liquid, such as water or oils, and foaming agents, where mixturesare typically 60% to 80% gas.

Examples of typical additives used in the hydraulic fracturing industryinclude: acids; alcohols; bases; biocides; buffers; breakers; claystabilizers and kcl substitutes; cross-linkers such as aluminum, boron,titanium, or zirconium; cross-link accelerators and delay agents;demulsifiers; foamers and defoamers, friction reducers; iron controlagents; cellulose and guar polymers including standard, hpg, cmg, cmhpg;polymer slurries, including diesel and “green”; oxygen scavengers;salts; surfactants; and flurosurfactants. This list of additives is onlya representative portion of all additives used and is not meant to be acomplete list.

Effectively dispersing a well-formulated fracturing fluid with a complexset of additives into a homogeneous emulsion is extremely difficult toaccomplish due, primarily, because of chemical affinity mismatches thatresult from the broad diversity of the additives used. Additionally,because of the toxic nature of some of the chemicals used in hydraulicfracturing, industry is facing stiff and growing environmentalregulation. Regulation is anticipated that will establish limits forvarious materials contained in hydraulic fracturing additives andcarrier fluids.

Due to environmental issues associated with hydraulic fracturing, theoil and gas industry has shifted towards using water with mineraladditives as the fracturing fluid of choice. The most commonly usedadditive in water hydraulic fracturing is a friction reducer.

Carrier fluids, additives and proppant must be mixed for use inhydraulic fracturing.

There are three types of commonly used mixing principles:

1. Static mixing, wherein liquids flow around fixed objects, either viaforce produced flow by pressure through mechanical means or gravityinduced flow;

2. Dynamic mixing, wherein liquid induced mixing results from mechanicalagitation via impellers, wiping blade and high shear turbines as well assingle or double screw extruder designs or screw agitation designs; and

3. Kinetic mixing, wherein liquid is mixed by velocity impacts on asurface or wherein two or more liquids form a velocity impact byimpinging on one another.

All three of the above mixing methods have one thing in common thathinders the optimizing of mixing regardless of the fluid being combinedand regardless of whether the materials being mixed are polar, nonpolar,organic or inorganic etc. or if it is a filled material withcompressible or non-compressible fillers.

The commonality that hinders optimizing of mixing is that allincompressible fluids have a wall effect or a boundary layer effectwhere the fluid velocity is greatly reduced at the wall or mechanicalinterface. Static mixing systems use this boundary layer to fold orblend the liquid using this resistive force to promote agitation.

Dynamic mixing, regardless of the geometry of mixing blades or turbine,results in dead zones and incomplete mixing because of the boundarylayer. Dynamic mixing uses high shear and a screw blade designed to usethe boundary layer to promote friction and compression by centrifugalforces to accomplish agitation while maintaining an incomplete mixedboundary layer on mechanical surfaces.

Kinetic mixing suffers from boundary layer effects on velocity profilesboth on the incoming streams and at the injector tip. However, kineticmixing suffers minimal boundary layer effects except for transport fluidphenomena.

A further explanation of the boundary layer of the flowing fluidsfollows. Aerodynamic forces depend in a complex way on the viscosity ofa fluid. As a fluid moves past an object, the molecules in closeproximity to the surface tend to stick to the surface. The moleculesjust above the surface are slowed down by their collisions with themolecules that are sticking to the surface. These molecules, in turn,slow down the flow just above them. The farther away from the surface,the fewer the collisions that are affected by the object surface.Therefore, a thin layer of fluid is created near the surface in whichthe velocity of the fluid changes from zero at the surface to the freestream value away from the surface. Engineers call this layer the“boundary layer” because the layer occurs on the boundary of the fluid.

As discussed above, as an object moves through a fluid, or as a fluidmoves past an object, molecules of the fluid near the object aredisturbed and as the molecules move around the object. Aerodynamicforces are generated between the fluid and the object. The magnitude ofthe aerodynamic forces depends on the shape of the object, the speed ofthe object, the mass of the fluid going by the object and on two otherimportant properties of the fluid, i.e., the viscosity, or stickiness,and the compressibility, or springiness, of the fluid. To properly modelthese effects, aerospace engineers use similarity parameters, which areratios of these effects to other forces present in the problem. If twoexperiments have the same values for the similarity parameters, then therelative importance of the forces are being correctly modeled.

Referring now to FIG. 1, a two dimensional representation of thestreamwise velocity variation from free stream to the surface is shown.In reality, the effects are three dimensional. From the conservation ofmass in three dimensions, a change in velocity in the streamwisedirection causes a change in velocity in the other directions as well. Asmall component of velocity perpendicular to the surface displaces ormoves the flow above it. The thickness of the boundary layer can bedefined as the amount of this displacement. The displacement thicknessdepends on the Reynolds number, which is the ratio of inertial(resistant to change or motion) forces to viscous (heavy and gluey)forces and is given by the equation: Reynolds number (Re) equalsvelocity (V) times density (r) times a characteristic length (1) dividedby the viscosity coefficient (mμ), i.e., Re=V*r*1/mμ.

Still referring to FIG. 1, boundary layers may be either laminar(layered), or turbulent (disordered) depending on the value of theReynolds number. For lower Reynolds numbers, the boundary layer islaminar and the streamwise velocity changes uniformly as a function ofdistance away from the wall, as may be seen on the left side of FIG. 1.For higher Reynolds numbers, the boundary layer is turbulent and thestreamwise velocity is characterized by unsteady, or changing with time,swirling flows inside the boundary layer. The external flow reacts tothe edge of the boundary layer just as it would to the physical surfaceof an object. Therefore, the boundary layer gives any object aneffective shape, which is usually slightly different from the physicalshape. The boundary layer may lift off or “separate” from the body andcreate an effective shape that is substantially different from thephysical shape. Separation occurs because the flow in the boundary hasvery low energy relative to the free stream and is, therefore, moreeasily driven by changes in pressure. Flow separation is the reason forairplane wing stall at high angle of attack.

Boundary-Layer Flow

The portion of a fluid flow that occurs near a solid surface is whereshear stresses are significant and is where inviscid-flow assumptionsmay not be used. Solid surfaces interact with a viscous fluid flowbecause of the no-slip condition discussed above, i.e., because of thephysical requirement that fluid and solid have equal velocities at theirinterface. Therefore, fluid flow is retarded by a fixed solid surface,which results in the formation of a finite, slow-moving boundary layer.For the boundary layer to be thin, the Reynolds number of the body mustbe large, i.e., 10³ or greater. Under these conditions the flow outsidethe boundary layer is essentially inviscid and plays the role of being adriving mechanism for the layer.

Referring now to FIG. 2, a typical low-speed or laminar boundary layeris shown. Such a display of the streamwise flow vector variation near awall is called a velocity profile. The no-slip condition requires thatu(x,0)=0, as shown, where u is the velocity of flow in the boundarylayer. Velocity rises monotonically with distance y from the wall,finally merging smoothly with the outer (inviscid) stream velocity U(x).Assuming a Newtonian fluid, at any point in the boundary layer the fluidshear stress τ is proportional to the local velocity gradient. The valueof the shear stress at the wall is most important, since the shearstress value relates not only to the drag of the body but often also toits heat transfer. At the edge of the boundary layer τ approaches zeroasymptotically. There is no exact spot where τ=0, therefore thethickness δ of a boundary layer is usually defined arbitrarily as thepoint where u=0.99 U.

Friction Reducers

As stated above, additives in hydraulic fracturing fluid are typicallydeployed for use as friction reducers. As shown in FIG. 3, experimentswere conducted wherein various friction reducers were added at aconcentration of 0.25 gpt in 2% (wt) Kcl tap water flowing through a ½″OD/0.402″ ID pipe. FIG. 4 shows experimental results comparing of 1.0gpt of cationic friction reducers in several different fluids through a½″ OD/0.402″ ID pipe. The graphs are discussed in SPE 119900, “CriticalEvaluations of Additives Used in Shale Slickwater Fracs”; (P. Kaufmanand G. S. Penny, CESI Chemical a Flotek Co. and J. Paktinat, UniversalWell Services Inc.)

Each of FIGS. 3 and 4 show that there are two clear regions where thedispersion of a typical material is greatly influenced, i.e., at 0 to 10seconds and again at 20 to 30 seconds. During the experiments, the fluidwas recycled back into the loop through the circulation pump every 10seconds. The circulation pump acted like a mixing system, therebyimproving the material performance of the additive. The experimentalresults, represented by the curves of FIGS. 3 and 4, illustrate thatdispersion of additives is crucial to the performance of the material.The periods of time from 0 to 10 second and from 20 to 30 secondscorrelate to the times when typical friction reduction material passesthrough the mixing system in the cyclic loop process. The shape of thecurves of FIGS. 3 and 4 indicate that, at about 10 seconds, the typicalmaterial has not been adequately dispersed and, therefore, is notdistributed into the boundary layer of the flowing material. Therefore,the important disbursement of additives is desirable.

SUMMARY OF THE INVENTION

The technology of the invention provides a unique solution to the abovementioned problems. The technology of the invention provides kineticmixing of the boundary layer, which allows for reduction or replacementof additives that may be environmentally damaging while stillmaintaining benefits associated with the additives. The technology ofthe invention uses environmentally safe, chemically stable solidparticles to continuously mix materials as long as the fluid is flowing.

The invention relates to improvements in boundary layer mixing, i.e.,the invention relates to the effects of structural mechanical fillers onfluid flow, wherein the particles have sizes ranging from nano tomicron. The invention uses the principles of boundary layer static filmcoupled with frictional forces associated with a particle being forcedto rotate or tumble in the boundary layer due to fluid velocitydifferentials. As a result, kinetic mixing is promoted through the useof the structural fillers.

As an example, consider that a hard sphere rolling on a soft materialtravels in a moving depression. The soft material is compressed in frontof the rolling sphere and the soft material rebounds at the rear of therolling sphere. If the material is perfectly elastic, energy storedduring compression is returned to the sphere by the rebound of the softmaterial at the rear of the rolling sphere. In practice, actualmaterials are not perfectly elastic. Therefore, energy dissipationoccurs, which results in kinetic energy, i.e., rolling. By definition, afluid is a material continuum that is unable to withstand a static shearstress. Unlike an elastic solid, which responds to a shear stress with arecoverable deformation, a fluid responds with irrecoverable flow. Theirrecoverable flow may be used as a driving force for kinetic mechanicalmixing in the boundary layer. By using the principle of rolling, kineticfriction and an increase of fluid sticking at the surface of the no-slipzone, adherents are produced. Fluid flow that is adjacent to theboundary layer produces an inertial force upon the adhered particles.Inertial force rotates the particles along the surface of mechanicalprocess equipment regardless of mixing mechanics used, i.e., regardlessof static, dynamic or kinetic mixing.

Geometric design or selection of structural filler particles is based onthe fundamental principle of surface interaction with the sticky film inthe boundary layer where the velocity is zero. Mechanical surfaceadherence is increased by increasing particle surface roughness.Particle penetration deep into the boundary layer produces kineticmixing. Particle penetration is increased by increasing sharpness ofparticle edges or bladelike particle surfaces. A particle having a roughand/or sharp particle surface exhibits increased adhesion to thenon-slip zone, which promotes better surface adhesion than a smoothparticle having little to no surface characteristics. The ideal fillerparticle size will differ depending upon the fluid due to the viscosityof a particular fluid. Because viscosity differs depending on the fluid,process parameters such as temperature and pressure as well as mixingmechanics produced by sheer forces and surface polishing on mechanicalsurfaces will also differ, which creates a variation in boundary layerthickness. A rough and/or sharp particle surface allows a particle tofunction as a rolling kinetic mixing blade in the boundary layer. Ahardened particle having rough and/or sharp edges that rolls along afluid boundary layer will produce micro mixing by agitating the surfacearea of the boundary layer exists.

Solid particles used for kinetic mixing in a boundary layer preferablyhave following characteristics:

-   -   Particles should have a physical geometry characteristic that        allows the particle to roll or tumble along a boundary layer        surface.    -   Particles shall have a surface roughness sufficient to interact        with a zero velocity zone or a non-slip fluid surface to promote        kinetic friction rather than static friction. The mixing        efficiency of particles increases with surface roughness.    -   Particles should be sufficiently hard so that the fluid is        deformed around a particle for promoting kinetic mixing through        the tumbling or rolling effect of the particle.    -   Particles should be size proportional to the boundary layer of        fluid being used so that the particles roll or tumble due to        kinetic rolling friction.    -   Particles should not be too small. If the particles are too        small, the particles will be caught in the boundary layer and        will lose the ability to tumble or roll, which increases        friction and promotes mechanical wear throughout the contact        zone of the boundary.    -   Particles should not be too large. If the particles are too        large, the particles will be swept into the bulk fluid flow and        have a minimal, if any, effect on kinetic boundary layer mixing.        The particles should have size and surface characteristics, such        as roughness and/or sharp bladelike characteristics, to be able        to reconnect in the boundary layer from the bulk fluid during        the mixing process.    -   Particles can be solid or porous materials, manmade or naturally        occurring minerals and or rocks.

Physical Geometry of Particles:

Particle shapes can be spherical, triangular, diamond, square or etc.,but semi-flat or flat particles are less desirable because they do nottumble well. Semi-flat or flat particles tumble less well because thecross-sectional surface area of a flat particle has little resistance tofluid friction applied to its small thickness. However, since agitationin the form of mixing is desired, awkward forms of tumbling arebeneficial since the awkward tumbling creates dynamic random generatedmixing zones at the boundary layer. Random mixing zones are analogous tomixing zones created by big mixing blades operating with little mixingblades. Some of the blades turn fast and some of the blades turn slow,but the result is that the blades are all mixing. In a more viscousfluid, which has less inelastic properties, kinetic mixing by particleswill produce a chopping and grinding effect due to particle surfaceroughness and due to sharp edges of the particles.

Spherical particles having extremely smooth surfaces are not ideal forthe following reasons. First, surface roughness increases frictionbetween the particle and the fluid, which increases the ability of theparticle to remain in contact with the sticky and/or the non-slip zone.In contrast, a smooth surface, such as may be found on a sphere, limitscontact with the sticky layer due to poor surface adhesion. Second,surface roughness directly affects the ability of a particle to inducemixing through tumbling and/or rolling, whereas a smooth surface doesnot. Thirdly, spherical shapes with smooth surfaces tend to roll alongthe boundary layer, which can promote a lubricating effect. However,spherical particles having surface roughness help to promote dynamicmixing of the boundary layer as well as promote lubricating effects,especially with low viscosity fluids and gases.

Advantages of this technology include:

-   -   Cost savings achieved by the replacement of expensive polymers        with inexpensive structural material.    -   Cost savings achieved by increasing an ability to incorporate        more organic material into a fluid.    -   Cost savings achieved by increasing productivity with high        levels of organic and/or structural materials.    -   Better disbursement of additives and/or fillers through        increased mixing on large mechanical surfaces produced by        boundary mixing.    -   Better mixing of polymers by grinding and cutting effects of the        particles rolling along the large surface area as the velocity        and compression of the polymers impact the surface during normal        mixing operations.    -   Reduction of coefficient of friction on mechanical surfaces        caused by boundary layer effects with drag which is replaced by        rolling kinetic friction of a hard particle in the boundary        layers.    -   Increased production by reduction of the coefficient of friction        in the boundary layer where the coefficient of friction directly        affects the production output.    -   Surface quality improvement, with or without fillers, due to        polish effects caused by kinetic mixing in the boundary layer on        all mechanical surfaces including dyes, molds and etc. that the        materials flow in and around during the finishing process.    -   Promotion of boundary layer removal by kinetic mixing, thereby        having the property of self-cleaning of the boundary layer.    -   Enhanced heat transfer due to kinetic mixing in the boundary        layer, which is considered to be a stagnant film where the heat        transfer is dominantly conduction but the mixing of the stagnant        film produces forced convection at the heat transfer surface.

The kinetic mixing material will help meet current and anticipatedenvironmental regulatory requirements by reducing the use of certaintoxic additives and replacing the toxic additives with anenvironmentally friendly, inert solid, i.e., kinetic mixing material,that is both chemically and thermally stable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical explanation of boundary layer concepts.

FIG. 2 is a graphical explanation of a low speed or laminar boundarylayer.

FIG. 3 is a graph showing data from a friction flow loop test comparingfriction reducers.

FIG. 4 is a graph showing data from a friction flow loop test comparingfriction reducers.

FIG. 5 is a schematic diagram of an in-line shear mixing system foradding sharp edged particles to a hydraulic fracturing fluid.

FIG. 6 is a schematic diagram of an in-line shear mixing system having arecycle loop wherein the system is for adding sharp edged particles to ahydraulic fracturing fluid.

FIG. 7 shows results of a slurry test.

FIG. 8 shows electron microscope images of crushed sand.

FIG. 9 is a schematic view of proppant particles having sharp edgedparticles dispersed therebetween in a formation fracture.

FIG. 10 is an SEM image of unprocessed expanded perlite.

FIG. 11 is an SEM image of processed perlite at 500× magnification.

FIG. 12 is an SEM image of processed perlite at 2500× magnification.

FIG. 13 is an SEM image of volcanic ash wherein each tick mark equals100 microns.

FIG. 14 is an SEM image of volcanic ash wherein each tick mark equals 50microns.

FIG. 15A is an SEM image of natural zeolite-templated carbon produced at700 C.

FIG. 15B is an SEM image of natural zeolite-templated carbon produced at800 C.

FIG. 15C is an SEM image of natural zeolite-templated carbon produced at900 C.

FIG. 15D is an SEM image of natural zeolite-templated carbon produced at1,000 C.

FIG. 16 is an SEM image of nano porous alumina membrane at 30000×magnification.

FIG. 17 is an SEM image of pseudoboehmite phase Al₂O₃×H₂O grown overaluminum alloy AA2024-T3 at 120,000 magnifcation.

FIG. 18 is an SEM image of unprocessed hollow ash spheres at 1000×magnification.

FIG. 19 is an SEM image of processed hollow ash spheres at 2500×magnification.

FIG. 20 is an SEM image of 3M® glass bubbles.

FIG. 21A is an SEM image of fly ash particles at 5,000× magnification.

FIG. 21B is an SEM image of fly ash particles at 10,000× magnification.

FIG. 22 is an SEM image of recycled glass at 500× magnification.

FIG. 23 is an SEM image of recycled glass at 1,000× magnification.

FIG. 24 is an SEM image of processed red volcanic rock at 750×magnification.

FIG. 25A is an SEM image of a sand particle that has the ability tofracture, which produces appropriate surface characteristics for kineticboundary layer mixing particles.

FIG. 25B is an SEM image of a sand particle that has the ability tofracture, which produces appropriate surface characteristics for kineticboundary layer mixing particles.

FIG. 25C is an SEM image of a sand particle that has the ability tofracture, which produces appropriate surface characteristics for kineticboundary layer mixing particles.

FIG. 25D is an SEM image of a sand particle that has the ability tofracture, which produces appropriate surface characteristics for kineticboundary layer mixing particles.

FIG. 26A is an SEM image of zeolite Y, A and silicate 1 synthesized for1 hour.

FIG. 26B is an SEM image of zeolite Y, A and silicate 1 synthesized for1 hour.

FIG. 26C is an SEM image of zeolite Y, A and silicate 1 synthesized for6 hours.

FIG. 26D is an SEM image of zeolite Y, A and silicate 1 synthesized for6 hours.

FIG. 26E is an SEM image of zeolite Y, A and silicate 1 synthesized for12 hours.

FIG. 26F is an SEM image of zeolite Y, A and silicate 1 synthesized for12 hours.

FIG. 27 is an SEM image of phosphocalcic hydroxyapatite.

FIG. 28A is an SEM image of Al MFI agglomerates.

FIG. 28B is an SEM image of Al MFI agglomerates.

FIG. 29A is an SEM image of microcrystalline zeolite Y at 20 k×magnification.

FIG. 29B is an SEM image of microcrystalline zeolite Y at 100 k×magnification.

FIG. 30 is an SEM image of ZnO, 50˜150 nm.

FIG. 31A is an SEM image of solid residues of semi-spherical clusteringmaterial.

FIG. 31B is an SEM image of zeolite-P synthesized at 100° C.

FIG. 32A is an SEM image of nanostructured CoOOH hollow spheres.

FIG. 32B is an SEM image of CuO.

FIG. 32C is an SEM image of CuO.

FIG. 33A is an SEM image of fused ash at 1.5N at 100° C.

FIG. 33B is an SEM image of fused ash at 1.5N at 100° C. 6 hours showingunnamed zeolite.

FIG. 33C is an SEM image of fused ash at 1.5N at 100° C. 24 hoursshowing cubic zeolite.

FIG. 33D is an SEM image of fused ash at 1.5N at 100° C. 72 hoursshowing unnamed zeolite and Gibbsite large crystal.

FIG. 34A is an SEM image of 2.5 um uniform plain Al₂O₃ nanospheres.

FIG. 34B is an SEM image of 635 nm uniform plain Al₂O₃ nanospheres.

FIG. 35 is a computer-generated model showing hair-like fibers of CoOOH

FIG. 36 shows two samples of rigid PVC with the same pigment loading inboth samples wherein one sample includes kinetic boundary layer mixingparticles.

FIG. 37 shows two samples of polycarbonate with the same pigment loadingin both samples wherein one sample includes kinetic boundary layermixing particles.

FIG. 38 shows a rigid PVC with ABS spots.

FIG. 39 shows PVC and ABS mixed together.

FIG. 40 sows a base polypropylene foam with direct gas injection, noadditive, wherein the cells size is 163 micron;

FIG. 41 shows a polypropylene foam with 4.8% additive of 27 mincornexpanded perlite with a cell size of 45 microns.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fracturing fluid of the invention is an improvement over knownhydraulic fracturing fluids in three areas. The first aspect of theinvention relates to the addition of a boundary layer kinetic mixingmaterial having micro/nano sized particles. A kinetic mixing material isa plurality of particles wherein at least 25% of the particles are ofseveral types, described below, having surface characteristics of one ofthin walls, three dimensional wedge-like sharp blades, points, jaggedbladelike surfaces, thin blade surfaces, three-dimensional blade shapesthat may have shapes similar to a “Y”, “V” or “X” shape or othergeometric shape, slightly curved thin walls having a shape similar to anegg shell shape, crushed hollow spheres, sharp bladelike features,protruding 90° corners that are sharp and well defined, conglomeratedprotruding arms in various shapes, such as cylinders, rectangles,Y-shaped particles, X-shaped particles, octagons, pentagon, triangles,and diamonds. The mixing mechanism that is required to establish kineticmixing with particles is that fluid must be moving. When fluid flowstops, kinetic mixing stops. For example, mechanical mixing systems areapplied at the surface to produce hydraulic fracturing fluids but themixing stops once fluid leaves the agitation zone. However, this is notthe case with kinetic mixing particles. Kinetic mixing particlescontinue to mix the fracture fluid all the way through the flow processthrough the agitation process, down the wellbore, into the hydraulicfractures until the fluid stops moving. The kinetic mixing material ismixed with an additive formulation prior to blending the additiveformulation into a carrier fluid and before injecting the mixture into awell. The kinetic mixing material may be added by the manufacturer of anadditive formulation. The second aspect of the invention involvesintroducing the additive formulation into a carrier fluid by mechanicalshear. The third aspect of the invention involves using kinetic boundarylayer mixing particles to promote mechanical interlocks between proppantgrains, which stabilizes a hydraulic fracture.

1. Adding a Micro/Nano Sized Kinetic Mixing Material into an AdditiveFormulation Prior to Blending the Mixing Material into a Carrier Fluidand Before Injecting the Mixing Material into the Well.

A kinetic mixing material made of micro/nano sized particles may beintroduced into an additive formulation. An example mixing material isdescribed in US Patent Publication Number 2010/0093922 for “StructurallyEnhanced Plastics with Filler Reinforcements” which is herebyincorporated by reference. The resulting improved mixing will produce asignificantly more homogeneous emulsion as compared to an additive andcarrier fluid mixture not having kinetic mixing material. Additionally,an emulsion containing the kinetic mixing material will exhibitself-dispersing properties when introduced into a carrier fluid.

As an example, an emulsion may be formulated that includes one gallonpolymer per thousand gallons of liquid wherein the kinetic mixingmaterial can start at a formula weight of as low as 0.05% and can beincreased up to 70% formula weight until desired performance is reached.The polymer may be a cross-linked water based fluid, an oil based fluid,an oil-in-water emulsion, a foam, or other suitable substance. Otherquantities and ratios are additionally contemplated as being effective.The above example is for illustration purposes only and should not beconstrued as limiting.

Forming an emulsion by introducing a kinetic mixing material into anadditive formulation prior to mixing with a carrier fluid can beaccomplished in various ways, including by using one of the followingthree mixing systems: turbine blade or impeller system; shear system; orimpingement system. The shear and impingement mixing systems can be usedto adjust the micro/nano sized kinetic mixing material into a particleof the desired size during the mixing process. The shear mixing systemhomogenizes the additives and may adjust the physical particle size ofthe micro/nano kinetic mixing material, depending on the type ofmaterial being used. Example materials include expanded perlite, fly ashand zeolite. Because of the porous geometry and thin cell walls, thesematerials are ideal candidates. In contrast, materials such as sand,granite, and other hard structural solids are less ideal since thesematerials will tend to damage mechanical shear blades.

Kinetic mixing particles can be made from a wide variety of materialswith varying densities and surface characteristics as illustrated by theSEM photograph in the figures. The variety allows someone skilled in artthe ability to select materials or a mixture of materials that will staysuspended in the operating fluid to achieve the desired performance.

Particle sizes may be adjusted up and down to produce steady suspensionin fluid materials.

2. Introducing the Additive Mixture into the Carrier Fluid by MechanicalShear.

A high-shear, in-line mixing system may be used to incorporate theadditive mixture into a carrier fluid prior to well injection. Theincorporation of the additive mixture prior to injection can beaccomplished by two methods:

First, the disbursement of additives can be improved by use of anin-line shear mixing system 10 (FIG. 5) with metering device 12.Metering device 12 precisely measures amounts of additives needed informulation 13. Examples of additives include well treatment polymers.The additives are measured prior to shear mixing into bulk carrier fluid16. The in-line shear mixing process equipment 14 is placed between acarrier fluid storage tank 16 and a well injection pumping system.Carrier fluid 16 with additive formulation 13, such as dispersedpolymer, will then be fed by feed pump 18 to the well injection pumpwhere proppant 24 will be added prior to well injection.

Second, an in-line shear mixing system 22 (FIG. 6) may be utilized withor without metering device 12 for measuring amounts of additiveformulation 13. In this embodiment, in-line shear mixing processequipment 14 is fed by feed pump 18 from the carrier fluid storage tank16 and the discharge from the in-line shear mixing process equipment 14is connected to recycle loop 22 that feeds back into carrier fluidstorage tank 16. This recycle process is continued until appropriatedispersion is achieved. Carrier fluid 16 with additive formulation 13,such as dispersed polymer, is then fed to a well injection pump whereproppant 24 will be added prior to well injection.

A concentration of powdered Kelzan® XCD polymer (available from KelcoOil Field Group, 10920 W. Sam Houston Parkway North, Suite 800, Houston,Tex. 77064) was flow tested. A (type I) boundary layer kinetic mixingparticle made from processed expanded perlite was used. The particleshad a mean particle size of 20 micron. The particles were added to thethoroughly mixed XCD polymer mixture at two different concentrations.The first concentration was at 5% by weight added directly into thecirculating fluid. The second concentration was 1%, which wasaccomplished by adding an additional 5% by weight to the circulatingfluid. The reason the Type I kinetic mixing particle was chosen isbecause the large bladelike characteristic of the Type I particlesproduce maximum mixing and/or dispersion with minimal fluid flow toproduce tumbling of particles. Perlite was chosen due to its glasscharacteristics that possess no surface charges, thereby avoidingconglomeration of particles, which allows for rapid disbursing of theparticles with minimal mixing.

A Marsh viscosity of 90 seconds was targeted. The mix ratio was 1 lb ofthe polymer per 10 gallons of water. After an initial mixing, thecombined materials were pumped from the storage tank, through thecirculation loop, and back to a storage tank where a turbine mixingsystem continuously agitated and circulated the tank in a configurationsimilar to that shown in FIG. 6. The mixing process continued for twohours to minimize or eliminate the possibility that the polymer was notthoroughly mixed to ensure fluids stabilization prior to taking baselinetesting. Then the boundary layer kinetic mixing particles were added tothe mixture.

The resulting thoroughly mixed XCD and water solution had a plasticviscosity of 12 cP and an apparent viscosity of 33.5 cP.

Laboratory testing has shown that the lower the viscosity of a fluid,the thinner the boundary layer. An oversized kinetic particle type (I)was chosen, i.e., a Type I particle approximately 20μ in diameter, toshow that large particles used for mechanical propannt interlocking havethe ability to still have a positive effect on the mixing properties ofa polymer. A appropriately sized kinetic mixing particle for a 33.5 cPfluid should be below 300 nm as a minimum. The 20μ kinetic particle istoo large for the adhesive effects of the viscosity at the wall of theboundary layer to hold onto the particle. The fluid forces flowing atthe boundary layer cause the particle to continuously bump against theboundary layer and then be swept back out into the bulk fluid flow. Atype (I) kinetic particle will still produce polymer kinetic mixing asit tumbles through the bulk fluid with minimal interaction with theboundary layer.

Tests were conducted with the same fluid at 0.5% and 1% concentration ofthe 20-micron kinetic mixing particle of the invention. The results canbe seen in the graph of FIG. 7, which shows a lower pressure drop of theflowing fluid when the particles were added. FIG. 7 shows that there isa consistent linear improvement to the flow rate which is contributed tobetter mixing of the polymer solution by the addition of a kineticboundary layer mixing particle. This data also illustrates thatoversized kinetic boundary layer mixing particles can be incorporatedinto hydraulic fracturing fluids with no adverse effects. Therefore,these oversized kinetic particles will provide a beneficial mechanicalinterlocking for proppants.

3. Tailoring Kinetic Mixing Material to Promote Mechanical InterlockingBetween Proppant Grains.

Proppant 24 may be modified in such a way as to impart upon it thecharacteristics necessary to become a kinetic mixing material 20. Forexample, sand may be roller milled to produce edge effects like thosediscussed in U.S. Patent Application Publication No. 2010/0093922,discussed above. Alternatively, the sand may be crushed. One example ofa machine that allows for production of grains of a desired size is theV7 dry sand making system, available from Kemco, a private Japanesecorporation based in Hiroshima, Japan. For example, as shown in FIG. 8,scanning electron images of artificially crushed quartz sand grains showfreshly broken surfaces in panes A, B, and D of the type that may bedescribed as a sharp blade-like surface. In particular, the brokensurfaces project edges defined by planes meeting at an angle of 90° orless. Pane C shows rounded surfaces not ideal for acting as a kineticmixing material. In a preferred embodiment, 0.5% to 100% of proppant 24can be comprised of crushed sand. Preferably, the crushed sand has amesh size of nano sized to approximately 20 mesh. By modifying theproppant 24 to have characteristics of a kinetic mixing material 20, theproppant 24 itself reduces the coefficient of friction caused byboundary layer interaction of the fracturing fluid flow and reduces theincreased load factor of proppant 24 presence in the well injectionfluid. It is possible to replace most if not all friction reductionpolymers, i.e., additives 13, by adding a modified proppant 24.

The areas of hydraulic fracturing fluid improvement discussed aboveimprove flow back reduction and proppant penetration into ahydraulically fractured formation, through improved bonding betweenproppant grains 24; improved stability of larger fractures comprised ofan opening that is greater than five diameters wide of proppant grain24; improved shear stress bearing stability of proppant 24; improvedstabilization of columns of proppant 24; improved crush strength ofproppant 24; improved proppant 24 penetration into fractured formation;and improved production through flow dynamics stabilization of proppant24. As fracture fluid is pumped into a well fracture, fracture fluidflow slows down and proppant grains 24 fall out. The kinetic mixingmaterial 20 settles out with proppant 24 and locates on and between theproppant grains 24 to jam in between the proppant grains 24 to preventrelative movement of the proppant grains 24. If kinetic mixing particles20 are selected from particle Type I, then porous materials or hollowspheres may be crushed by the proppant 24, which results in goodinterspersing of the kinetic mixing particles as in self-shapinginterlocking between the proppant 20, as shown in FIG. 9.

The above listed benefits accrue from an increased ability to stackproppant grains 24 to support an opened fracture. The stacking of roundobjects on top of each other to produce a large load-bearing structuresupported by all of the round objects under the load is a difficultendeavor.

Still referring to FIG. 9, in one embodiment, the kinetic mixingmaterial 20 of the present invention is comprised of light-weightparticles (Types I, II), high-strength particles (Types I-V), andprimarily chemically and thermodynamically stable particles. Examplekinetic mixing particles of Types I-IV) includes particles having aparticle geometry that acts like a mechanical locking mechanism betweenthe interfaces of proppant grains 24, thereby increasing the coefficientof friction between the individual proppant grains 24, thereby creatinga stable load-bearing, proppant-supported fracture. The particle typesare discussed in greater detail below.

Particle Type I

Particle type I embeds deep into the boundary layer to produce excellentkinetic mixing in both the boundary layer and in the mixing zone. Type Iparticles increase dispersion of chemical and mineral additives. Type Iparticles increase fluid flow. The surface area of Type I particles islarge compared to the mass of Type I particles. Therefore Type Iparticles stay in suspension well.

Referring to FIG. 10, shown is expanded perlite that is unprocessed.Perlite is a mineable ore with no known environmental concerns and isreadily available on most continents and is only surpassed in abundanceby sand. Expanded perlite is produced through thermal expansion processwhich can be tailored to produce a variety of wall thicknesses of thebubbles. Expanded perlite clearly shows thin wall cellular structure andhow it will deform under pressure. In one embodiment, perlite may beused in a raw unprocessed form, which is the most economic form of thematerial. Process equipment that is used for mixing and/or thehigh-pressure well environment may produce the desired particle shapesbecause of Perlite's ability to self-shape under pressure into boundarylayer kinetic mixing particles. Perlite provides ideal mechanicalinterlocking properties to produce stable structural columns throughouta fracture when used in hydraulic fracturing fluid due to its sillierstructure and its ability to self-shape. The approximate applicationsize is 900μ to 10,000μ. The self-shaped size is estimated to be 100μ orless. This material produces excellent performance in the boundarylayers having viscosity materials such as thermoplastics and drillingmud this kinetic mixing particle produces dispersion in a variety ofviscosity materials from high low as well as being an excellentnucleating agent and foaming processes.

Referring to FIG. 11, shown is an image that demonstrates that theexpanded perlite particles do not conglomerate and will flow easilyamong other process particles. Therefore, expanded perlite particleswill easily disperse with minimal mixing equipment.

Referring to FIG. 12, shown is an enlarged image of an expanded perliteparticle showing a preferred structural shape for processed perliteparticles. The particles may be described as having three-dimensionalwedge-like sharp blades and points with a variety of sizes. Theirregular shape promotes diverse kinetic boundary layer mixing. Theexpanded Perlite shown in FIG. 12 is extremely lightweight, having adensity in the range of 0.1-0.15 g/cm. This allows for minimal fluidvelocity to promote rotation of the particle. The bladelikecharacteristics easily capture the kinetic energy of the fluid flowingover the boundary layer while the jagged bladelike characteristicseasily pierce into the boundary layer promoting agitation whilemaintaining adherence to the surface of the boundary layer. Thepreferred approximate application size is estimated to be 50μ to 900 nm.This material produces excellent performance in the boundary layer offluids of viscous materials such as thermoplastics and drilling mud.This kinetic mixing particle produces dispersion in a variety of fluidshave viscosities ranging from high to low. Additionally, the particle isan excellent nucleating agent in foaming processes.

Referring now to FIG. 13, shown is volcanic ash in its natural state.Volcanic ash exhibits similar characteristics to the characteristics ofexpanded perlite, discussed above, regarding the thin walled cellularstructures. Volcanic ash is a naturally formed material that is readilymineable and that can be easily processed into a kinetic mixing materialthat produces kinetic boundary layer mixing. The volcanic ash materialis also deformable, which makes it an ideal candidate for in-lineprocesses to produce the desired shapes either by mixing or pressureapplied during the pumping process in the wellbore. The volcanic ashmaterial provides the same wedging effects as the Perlite discussedabove to produce mechanical locking between proppant grains, therebyproducing stable fracture openings. The preferred approximateapplication size is 900μ to 10,000μ. The self-shaping size is estimatedto be 100μ or less.

Referring now to FIG. 14, shown is a plurality of crushed volcanic ashparticles. FIG. 14 illustrates that any crushed particle form tends toproduce three-dimensional bladelike characteristics, which will interactin the boundary layer in a similar manner to expanded perlite, discussedabove, in its processed formed. This material is larger than theprocessed perlite making its application more appropriate to higherviscosity materials such as thermoplastics, lubricating grease anddrilling mud. However, the material is suitable for use as mechanicalinterlock between proppants and the fracture regardless of the viscosityof the fracturing fluid being pumped. The preferred approximateapplication size is estimated to be between 80μ to 30μ. This materialwill function similar to the processed perlite materials discussedabove.

Referring now to FIGS. 15A-15D, shown is natural zeolite-templatedcarbon produced at 700 C. (FIG. 15A), 800 C. (FIG. 15B), 900 C. (FIG.15C), and 1000 C. (FIG. 15 D). Zeolite is a readily mineable materialwith small pore sizes that can be processed to produce desired surfacecharacteristics of kinetic mixing material. Processed perlite andcrushed volcanic ash have similar boundary layer interactioncapabilities. Zeolites have small porosity and can, therefore, produceactive kinetic boundary layer mixing particles in the nano range. Thepreferred approximate application size is estimated to be between 900 nmto 600 nm. These materials are may be too small to be used as mechanicalinterlocks in any hydraulic fracturing formation. However, the particlesare ideal for friction reduction in medium viscosity materials such ascrude oil for hydraulic fracturing.

Referring now to FIG. 16, shown is a nano porous alumina membrane havinga cellular structure that will fracture and create particlecharacteristics similar to any force material. Material fractures willtake place at the thin walls, not at the intersections, therebyproducing characteristics similar to the previously discussed materials,which are ideal for boundary layer kinetic mixing particles. Thepreferred approximate application size is estimated to be between 500 nmto 300 nm. The particle sizes of this material are more appropriatelyapplied to medium to low viscosity fluids such as refined oils.

Referring now to FIG. 17, shown is a pseudoboehmite phase Al₂O₃×H₂Ogrown over aluminum alloy AA2024-T3. Visible are bladelikecharacteristics on the surface of processed Perlite. The fracture pointof this material is at the thin blade faces between intersections whereone or more blades join. Fractures will produce a three-dimensionalblade shape similar to a “Y”, “V” or “X” shape or similar combinationsof geometric shapes. The preferred approximate application size isestimated to be from 150 nm to 50 nm. The acceptable particle size rangeof this material makes it useful in water, radiator fluid, shearthinning hydraulic fracturing fluids.

Particle Type II

Particle type II achieves medium penetration into a boundary layer forproducing minimal kinetic boundary layer mixing and minimal dispersioncapabilities. Type II particles result in minimal enhanced fluid flowimprovement and are easily suspended based on the large surface andextremely low mass of Type II particles.

The majority of materials that form hollow spheres can undergomechanical processing to produce egg shell-like fragment with surfacecharacteristics to promote kinetic boundary layer mixing.

Referring now to FIG. 18, shown is an image of unprocessed hollowspheres of ash. Ash is mineable material that can undergo self-shapingto produce kinetic boundary layer mixing particle characteristicsdepending on process conditions. The preferred approximate applicationsize is estimated to be 80μ to 20μ prior to self-shaping processes.Self-shaping can be achieved either by mechanical mixing wellbore orpressure producing, either of which produce a crushing effect. Thismaterial could be used for a mechanical locking system for proppants toprovide dimensional stability to a formation fracture.

Referring now to FIG. 19, shown are processed hollow spheres of ash. Thefractured ash spheres will tumble in a boundary layer similar to a pieceof paper on a sidewalk. The slight curve of the material is similar to apiece of egg shell in that the material tends to tumble because of itslight weight and slight curvature. Preferred approximate applicationsize is estimated to be between 50 nm to 5 nm. This material willfunction similar to expanded perlite but it possesses an inferiordisbursing capability because its geometric shape does not allowparticles to become physically locked into the boundary layer due to thefact that two or more blades produces more resistance and betteragitation as a particle tumbles along the boundary layer. This materialreduces friction of heavy viscosity materials such as thermoplastics anddrilling mud.

Referring now to FIG. 20, shown are 3M® glass bubbles that can beprocessed into broken eggshell-like structure to produce surfacecharacteristics to promote kinetic boundary layer mixing. The particlesthat are similar in performance and application to the ash hollowspheres except that the wall thickness and diameter as well as strengthcan be tailored based on process conditions and raw material selections.These man-made materials can be used in food grade applications. Thepreferred approximate application size is estimated to be from 80μ to 5μprior to self-shaping processes either by mechanical mixing or bywellbore pressure that produce a crushing effect.

Referring now to FIG. 21, shown is an SEM photograph of fly ashparticles×5000 (FIG. 21A) and zeolite particles×10000 (FIG. 21B). Theparticles comprise hollow spheres. Fly ash is a common waste productproduced by combustion. Fly ash particles are readily available andeconomically affordable. Zeolite can be mined and made by an inexpensivesynthetic process to produce hundreds of thousands of variations.Therefore, desirable characteristics of the structure illustrated bythis hollow zeolite sphere can be selected. The zeolite particle shownis a hybrid particle, in that the particle will have surfacecharacteristic similar to processed perlite and the particle retains asemi-curved shape like an egg shell of a crushed hollow sphere. Thepreferred approximate application size is estimated to be from 5μ to 800nm prior to self-shaping processes. Self-shaping may be accomplishedeither by mechanical mixing or by wellbore pressure to produce acrushing effect. The small size of these particles make the particlesless than ideal for use as a mechanical anchoring system for proppants,but can be used for medium viscosity materials.

Particle Type III

Particle type III result in minimal penetration into a boundary layer.Type III particles result in minimal kinetic mixing in the boundarylayer and have excellent dispersion characteristics with both softchemical and hard mineral additives. Type II particles increase fluidflow and do not suspend well but are easily mixed back into suspension.

Some solid materials have the ability to produce conchordial fracturingto produce surface characteristics to promote kinetic boundary layermixing.

Referring now to FIGS. 22 and 23, shown are images of recycled glass.Recycled glass is a readily available man-made material that isinexpensive and easily processed into kinetic boundary layer mixingparticles. The sharp bladelike characteristics of the particles areproduced by conchordial fracturing similar to a variety of othermineable minerals. The bladelike characteristics of these particles arenot thin like perlite. The density of the particles is proportional tothe solid that is made from. The sharp blades interact with a fluidboundary layer in a manner similar to the interaction of perlite exceptthat the recycled glass particles require a viscous material and arobust flow rate to produce rotation. Processed recycled glass has nostatic charge. Therefore, recycled glass produces no agglomerationduring dispersion. However, because of its high density it can settleout of the fluid easier than other low-density materials. The preferredapproximate application sizes are estimated to be between 200μ to 5μ.This material produces good performance in boundary layers of heavyviscosity fluids with high flow rates such as thermoplastics anddrilling mud. This kinetic mixing particle produces dispersion. Thismaterial is suitable for producing good mechanical interlocks betweenproppants, thereby shoring up fractures. The smooth surface of theparticles reduces friction allowing good well production.

Referring now to FIG. 24, shown is an image of processed red lavavolcanic rock particles. Lava is a readily available mineable material.A typical use for lava is for use as landscape rocks in the AmericanSouthwest and in California. This material undergoes conchordialfracturing and produces characteristics similar to recycled grass.However, the fractured surfaces possess more surface roughness than thesmooth surface of the recycled glass. The surface characteristicsproduce a slightly more grinding effect coupled with bladelike cuttingof a flowing fluid. Therefore, the particles not only tumble, they havean abrasive effect on the fluid stream. The volcanic material dispersessemi-hard materials throughout viscous mediums such as fire retardants,titanium, calcium carbonate, dioxide etc. The preferred approximateapplication sizes are estimated to be between 40μ to 1μ. This materialproduces good performance in the boundary layer of flowing heavyviscosity materials at high flow rates such as thermoplastics anddrilling mud. This kinetic mixing particle produces dispersion. Thismaterial is can produce good mechanical interlocks between proppants.

Referring now to FIGS. 25A-25D, FIGS. 25A-C show sand particles thathave the ability to fracture, which produces appropriate surfacecharacteristics for kinetic boundary layer mixing particles. The imagesshow particles having similar physical properties to recycled glass,which produces similar benefits. Images A, B, D have good surfacecharacteristics for interacting with the boundary layer even though theyare different. Image A shows some bladelike characteristics but goodsurface roughness along edges of the particle to promote boundary layersurface interaction but will require higher velocity flow rates toproduce tumbling. Image B has similar surface characteristics to thesurface characteristics of recycled glass as discussed previously. ImageD shows particles having a good surface roughness to promote interactionsimilar to the interaction of these materials generally. The performanceof these particles is similar to the performance of recycled glass. Sandis an abundant material that is mineable and can be processedinexpensively to produce desired fractured shapes in a variety of sizes.Sand is considered environmentally friendly because it is a naturalmaterial. The preferred approximate application sizes are estimated tobe between 250μ to 5μ. This material produces good performance in theboundary layers of heavy viscosity materials at high flow rates such asthermoplastics and drilling mud. This kinetic mixing particle producesdispersion. This material is can produce good mechanical interlocksbetween proppants, thereby shoring up fractures. The smooth surface ofthe particles reduces friction, thereby allowing good well production.

Referring now to FIGS. 26A-26F, shown are images of Zeolite Y, A andSilicate-1. The SEM images of films synthesized for 1 h (a, b), 6 h (c,d) and 12 h (e, f) in the bottom part of a synthesis solution at 100 C.These materials can be processed to produce nano sized kinetic boundarylayer mixing particles. This material is synthetically grown and islimited in quantity and is, therefore, expensive. All six images, i.e.,images a, b, c, d, e, f clearly show the ability of this material toproduce conchodial fracturing with bladelike structures similar to thestructures mentioned above. The preferred approximate application sizeis estimated to be between 1000 nm to 500 nm. The particle size range ofthis material makes it useful in medium viscosity fluids such as refinedoils.

Referring now to FIG. 27, shown is phosphocalcic hydroxyapatite, formulaCa₁₀(PO₄)₆(OH)₂, forms part of the crystallographic family of apatites,which are isomorphic compounds with the same hexagonal structure. Thisis the calcium phosphate compound most commonly used for biomaterial.Hydroxyapatite is mainly used for medical applications. The surfacecharacteristics and performance are similar to those of red lavaparticles, discussed above, but this image shows a better surfaceroughness than the particle shown in the red lava image.

Particle Type IV

Some solid clustering material have the ability to produce fracturing ofthe cluster structure to produce individual unique uniform materialsthat produce surface characteristics to promote kinetic boundary layermixing.

Referring now to FIG. 28A and 28B, shown are SEM images of Alfoam/zeolite composites after 24 h crystallization tie at differentmagnifications. FIG. 28A shows an AL form/zeolite strut. FIG. 28B showsMFI agglomerates. The two images that show an inherent structure of thismaterial that will readily fracture upon mechanical processing toproduce irregular shaped clusters of the individual uniquely formedparticles. The more diverse a material's surface characteristics, thebetter the material will interact with the sticky nonslip zone of aflowing fluid's boundary layer to produce kinetic boundary layer mixing.This material possesses flowerlike buds with protruding random 90°corners that are sharp and well defined. The corners will promotemechanical agitation of the boundary layer. The particles also have asemi-spherical or cylinder-like shapes that will allow the material toroll or tumble while maintaining contact with the boundary layer due tothe diverse surface characteristics. The preferred approximateapplication size of the particles is estimated to be between 20μ to 1μ.This material could be used in a high viscosity fluid. The surfacecharacteristics will produce excellent dispersion of hardened materialssuch as fire retardants, zinc oxide, and calcium carbonate. As thismaterial is rolled, the block-like formation acts like miniature hammermills that chip away at the materials impacting against the boundarylayer as fluid flows by.

Referring now to FIGS. 29A and 29B, shown is an SEM image ofmicrocrystalline zeolite Y (FIG. 29A) and an SEM image ofnanocrystalline zeolite Y (FIG. 29B). The particles have all the samecharacteristics on the nano level as those mentioned in thefoam/zeolite, above. In 29A, the main semi-flat particle in the centerof the image is approximately 400 nm. In 29B, the multifaceted dots areless than 100 nm in particle size. Under mechanical processing, thesematerials can be fractured into diverse kinetic boundary layer mixingparticles. The preferred approximate application size is estimated forthe cluster material of 29A to be between 10μ to 400 nm and for clustermaterial of 29B to be between 50 nm to 150 nm. Under high mechanicalsheer, these clustering materials have the ability to self-shape byfracturing the most resistant particle that is preventing the clusterparticle from rolling easily. Due to their dynamic random rotationalability, these cluster materials are excellent for use as frictionmodifiers.

Referring now to FIG. 30, shown are zinc oxide particles of 50 nm to 150nm. Zinc oxide is an inexpensive nano powder that can be specialized tobe hydrophobic or to be more hydrophilic depending on the desiredapplication. Zinc oxide forms clusters having extremely random shapesThis material works very well due to its resulting random rotationalmovement in a flowing fluid. The particles have diverse surfacecharacteristics with 90° corners that create bladelike characteristicsin diverse shapes. Surface characteristics include protruding arms thatare conglomerated together in various shapes such as cylinders,rectangles, cues, Y-shaped particles, X-shaped particles, octagons,pentagon, triangles, diamonds etc. Because these materials are made outof clusters having diverse shapes the materials produce enormousfriction reduction because the boundary layer is churned to be as closeto turbulent as possible by diverse mechanical mixing while stillmaintaining a laminar fluid flow.

Particle Type V

Particles of Type V result in medium penetration into the boundarylayer. Type V particles create medium kinetic mixing of the boundarylayer similar to a leaf rake on dry ground. Type five particles haveexcellent adhesive forces to the gluey region to the boundary layer,which is required for two-phase boundary layer mixing. Particle Type Vproduces minimal dispersion of additives, therefore increases fluid flowand will tend to stay in suspension. Some hollow or solid semi-sphericalclustering material with aggressive surface morphology, e.g., roughness,groups, striations and hair-like fibers, promote excellent adhesion tothe boundary layer with the ability to roll freely and can be used inlow viscosity fluids and phase change materials, e.g., liquid to a gasand gas to a liquid. They possess the desired surface characteristics topromote boundary layer kinetic mixing.

Referring now to FIGS. 31A and 31B, shown is a scanning electronmicrograph of solid residues (31A) and a scanning electron micrographand energy dispersive spectroscopy (EDS) area analysis of zeolite-Psynthesized at 100 C. Unlike the cluster materials discussed in particletype IV, these materials have a spherical shape and a surface roughnessthat may be created by hair-like materials protruding from the surfaceof the particles. Image (a) shows a particle that possesses goodspherical characteristics. A majority of the spheres have surfaceroughness that is created by small connecting particles similar to sandgrains on the surface. Image (b) shows a semi-circular particle that hashair-like fibers protruding from the entire surface. Thesecharacteristics promote good adhesion to the boundary layer but notexcellent adhesion. These materials must roll freely on the surface ofthe boundary layer to produce minimal mixing to promote kinetic boundarylayer mixing in a two-phase system. For example, as a liquid transitionsto a gas in a closed system the boundary layer is rapidly thinning. Theparticles must stay in contact and roll to promote kinetic boundarylayer mixing. The material also must have the ability to travel withinthe gas flow to recycle back into the liquid to function as an activemedium in both phases. These particles have a preferred size range ofbetween approximately between 1μ to 5μ (FIG. 31A) and from betweenapproximately 20μ to 40μ (FIG. 31B). They both would work well in a highpressure steam generation system where they would move the stagnant filmon the walls of the boiler from conduction toward a convection heattransfer process.

Particle Type VI

Referring now to FIGS. 31 A, B, C, shown are nanostructured CoOOH hollowspheres that are versatile precursors for various cobalt oxide datives(e.g. Co₃O₄, LiCoO₂) and also possess excellent catalytic activity. CuOis an important transition metal oxide with a narrow bandgap (e.g., 1.2eV). CuO has been used as a catalyst, a gas sensor, in anode materialsfor Li ion batteries. CuO has also been used to prepare high temperaturesuperconductors and magnetoresistance materials.

Referring now to FIGS. 33 A, B, shown is a 2.5 μm uniform plain Al₂O₃nanospheres (FIG. 33A) and 635 nm uniform plain Al₂O₃ nanosphers havinghair-like fibers on the surface.

Referring now to FIG. 34, shown is a computer generated model that shownhair-like fibers that promote boundary layer adhesion so that nano-sizedparticles will stay in contact with the boundary layer while rollingalong the boundary layer and producing kinetic mixing.

Dispersion Properties of Boundary Layer Kinetic Mixing Particles

The kinetic boundary layer mixing technology has excellent dispersioncapabilities illustrated by FIGS. 36 and 37.

FIG. 36 shows a rigid PVC with the same pigment loading in both samples.It can clearly be seen that left sample having the kinetic boundarylayer mixing particles therein is dispersed better.

FIG. 37 shows polycarbonate with the same pigment loading in bothsamples. It can clearly be seen that the one that the sample on theright includes the kinetic boundary layer mixing particles and isdispersed better.

FIGS. 36 and 37 clearly illustrate the benefits of kinetic boundarylayer mixing particles in relationship to dispersion. The improveddispersion properties allows hydraulic fracturing fluids to have lessadditives because the presence of kinetic mixing fluid disburses theadditives better, thereby producing the same beneficial properties of anadditive.

Mixing and Blending of Dissimilar Materials

FIG. 38 shows two images. Image 1 shows rigid PVC with ABS spots. Thesetwo materials, even under high shear conditions chemically do not wantto mix or blend together.

Image 2 of FIG. 38 shows the effect the adding kinetic boundary layermixing particles on dissimilar hard to mix materials. In the extruder,the PVC and ABS mixed together, which resulted in the ABS acting like ablack pigment.

The improved mixing will permit the hydraulic fracturing industry totrying new additives that are more environmentally friendly and thatwere previously unsuitable due to failure to sufficiently mix or blendinto their hydraulic fracturing fluid.

Foam Nucleating Improvement.

The kinetic boundary layer mixing material can function as a highlyspecialized structural material. For example, sharp edged particles,when they are incorporated with a foaming agent, provide kinetic mixingthat does not stop when the mixing step is done. The particles continueto remain active as the fluid moves during the expansion process. Thispromotes better dispersion of the blowing agents as well as increasedmobility through better dispersion of reactive and nonreactive additivesthroughout the fluid during expansion of the foam thereby improvingcellular consistency. The unique characteristics of three-dimensional,pointed, blade-like structures of the kinetic mixing material producesexcellent nucleation sites, thereby increasing cellular wallconsistencies and strength. One type of hydraulic fracturing fluid isfoam. Kinetic boundary layer mixing particles will allow the foam toflow better and produce higher pressures down the wellbore because ofmore uniform micro cellular structures. This phenomenon can be seen bycomparing polypropylene foam with no additive (FIG. 40) and polypylenfoam with 4.8% additive of 27 micron expanded perlite (FIG. 41). FIG. 41shows a substantial improvement in producing micro cell structures.

One difficulty associated with drilling fluids is the tendency fordifferential sticking to occur. Kinetic mixing particles can be used toreduce the tendencies of differential sticking and to reduce thetendency of clay solids to adhere to metal surfaces and to each other.Accretion testing and dynamic filtration testing was conducted. Theaccretion test was conducted to assess a tendency of reactive solids toadhere to each other and to metal surfaces, such as a bit and drillstring. The result of the test materials were compared to the basedrilling fluid without any kinetic mixing particles. Dynamic filtrationstudies are typically conducted to determine how the circulation rateaffects high temperature, high pressure filtration rates. In this case,the testing showed that varying the circulation rate will cause acorresponding increase in filtration and a thinner filter cake as theconcentration of the test materials was increased.

The procedure used involved incorporating kinetic mixing material at 3concentrations in a typical lignite/lignosulfonate drilling fluid. Thebase fluid had the following formulation:

Tapwater.bbls 0.84 Bentonite.lb/bbl 20 Lignosulfinate.lb/bbl 4Lignite.lb/bbl 4 Caustic Sode.lb/bbl Tp pH of 9.5 to 10.5 Barite.lb/bbl178.5

The base fluid was hot rolled at 150° for 16 hours to stabilize theproperties prior to use in the testing. After hot roll, the base mud hada yield point of 9 lbs/100 ft². The base mud was then split into 4aliquots and incorporated into the fluids using a Silverson Mixer. TheSilverson Mixer was used to impart high shear and to develop thetemperature needed to incorporate the lubricant into the base fluids.The fourth aliquot served as the base. These fluids were then used inthe accretion and Dynamic Filtration tests.

Accretion Test

Each test fluid was loaded with 100 lb/bbl of Pierre Shale, which is amoderately reactive shale, and placed in individual hot roll cells.Clean, tared mild steel rods were placed in each cell and the cells weresealed. The cells were then hot rolled at 150° F. for 16 hours. Afterhot rolling, the cells were cooled to room temperature and the rodscarefully removed, gently cleaned with IPA, dried at 105° C. for 4 hoursand reweighed. The accretion results were calculated from thisinformation. The results follow:

BASE Ecopuro Boundary Breaker Sample Concentration, g 0 0.5 1.0 3.0 RodSurface Area, in³ 4.54 4.46 4.54 4.45 Clay Retained on Rod, g/n³ 0.3970.387 0.333 0.317 Improvement from Base, % — 2.52 16.12 20.15

Dynamic Filtration Test

An OFI Dynamic filtration apparatus was used for these tests. Each testfluid was placed in a dynamic filtration cell and tested at 3 differentrpm values. It was hoped that the filtration rates would be higher andthe filter cakes would be thinner thereby showing that the solids didnot have a tendency to stick to each other. Filtration test parameterswere 600 psi, differential pressure and 250° F. for 30 minutes. Thefiltration tests were run at 100 rpm, 300 rpm and 500 rpm. The resultsfollow:

BASE Ecopuro Boundary Breaker Sample Concentration, g 0 0.5 1.0 3.0Filtrate @ 100 rpm, ml 4.8 3.6 3.6 4.0 Filtrate @ 300 rpm, ml 3.8 4.34.2 3.8 Filtrate @ 500 rpm, ml 3.8 4.2 4.2 3.6

Further research indicates that this testing shows that a type I kineticmixing particle from expanded perlite around 20μ can reduce processsurface adhesion by 20%. This will result in the reduction of energy indrilling fluids which use bentonite clay. This also clearly shows bymoving the boundary layer of a thick viscous material from italicsurfaces can reduce of wall caking.

The fundamental shapes of porous materials similar to expanded perliteor pumice, or spherical material such as glass beads or volcanic ashspheres, create highly specialized shapes when crushed. Expanded perliteand pumice materials both exhibit bubble-like structures. The structuresare strongest at the intersection of the bubbles so the structures crackand break at the weakest point, which is along the bubble walls.Therefore, when the bubble-like structures are fractured, structureswith three-dimensional bladelike shapes (see, e.g., Particles Type I,FIGS. 10-17) are produced. These bladelike structures of kinetic mixingmaterial 20 produce mechanical wedging between the interface of proppantgrains 24.

Hollow spheres, e.g., Particles Type II, shown in FIGS. 18-21B, may alsobe used as kinetic mixing material 20. When hollow spheres undergocrushing during a milling process, or the drilling bore well pressuresreach 4000 psi or higher, the crushed or cracked particles producesemi-curved, egg-shaped structures that act as a mechanical wedgebetween proppant portions. These shaped structures will increase bondingbetween proppant grains 24 by a mechanical interlocking that resemblesplacing doorstops or wedges between every proppant grain 24, thereforeincreasing static friction between proppant grains 24. Therefore,individual grains of proppant 24 become mechanically interlocked byincreasing the friction between proppant grains 24, thereby preventingproppant grains 24 from rolling or moving when pressure is applied. Thisallows for a larger, more stable fracture to be formed. Additionally,The bladelike structure of the lightweight kinetic mixing material 20allows the mixing material to flow into regions of the formationfracture that had no prior flow.

The load-bearing dynamics of mechanical forces applied to semi sphericalparticles, such as proppant grains 24, are unique, because the particles24 are allowed to move against one another to relieve the load bearingstresses, which produces random columns of load-bearing points where thefriction among particles are semi-stable. The addition of kinetic mixingmaterial 20 reduces the ability of the semi-spherical proppant particles24 to roll by adding mechanical friction between the interfaces of theproppant particles 24, thereby increasing the load-bearing capabilitiesof the proppant 24. When the load-bearing proppant particles 24 areinterlocked, a more uniform load bearing strength is produced over theentire fracture thereby reducing proppant crushing and increasingstabilization of the fracture.

Lower Drag with Proppant Slurry

The boundary layer is the area of the highest drag of a fluid. Theboundary layer occurs at all fluid interfaces with fixed objects orsurfaces. Kinetic mixing material 20 is designed to move the boundarylayer of a flowing fluid which results in friction reduction insemi-viscous material or heavily filled materials such as proppantslurry. Kinetic mixing material 20 functions kinetically, i.e., thehigher the fluid flow velocity, the better kinetic mixing material 20performs to reduce friction; thereby increasing the penetration of aslurry into a fracture formation. As the fluid velocity slows down,kinetic mixing material 20 will migrate into the proppant slurrycreating an interlocking matrix.

The kinetic mixing material will help meet current and anticipatedenvironmental regulatory requirements by reducing the use of certaintoxic additives and replacing the toxic additives with anenvironmentally friendly, inert solid, i.e., kinetic mixing material,that is both chemically and thermally stable.

Typical proppant particle sizes are 20 mesh, i.e., 841 micron to 40mesh, i.e., 400 micron and 70 mesh, i.e., 210 micron. Sizes of kineticmixing material particles 20 to reduce flow back of proppant 24 andincrease fracture stability is from 1/32 to ¼ of the proppant sizeunless the mixing material is self-shaping, which enables largerparticle sizes because the particles will change geometrical shapesbased on operating conditions.

For example: 1/32 ¼ 20 mesh i.e., 841 μ: 26 μ 210 μ 40 mesh, i.e., 400μ: 12 μ 100 μ 70 mesh, i.e., 210 μ:  7 μ  52 μ

In one embodiment, kinetic mixing material 20 is perlite. There is aunique characteristic associated with perlite. Perlite can be added inexpanded form without undergoing milling process depending on the depthof the well. Perlite has a unique self-shaping property, as illustratedby the FIGS. 10-17. Under pressure, perlite naturally decomposes to theappropriate shapes required to interlock the proppant particles 24.Therefore, perlite can either be milled to a designated size or allowedto undergo a self-shaping process where the wellbore pressures reach4000 psi or higher. Expanded perlite's bubble fracture point is around500 psi depending on process conditions during the expansion.

Kinetic mixing material 20 may be mixed into a proppant slurry as a drypowder either as expanded bubbles which will self-shape or as apre-process milled version of a designated size. Kinetic mixingmaterials 20 may be added in at percentages ranging from 0.5% to 85% byweight fluid prior to addition of proppant 24.

Kinetic mixing material 20 used for kinetic mixing in boundary layer offracture fluid has the following characteristics:

-   -   The physical geometry of particles 20 should have a        characteristic that allows particle 20 the ability to roll or        tumble along the boundary layer of flowing fracture fluid.    -   Particles 20 may be irregularly shaped, e.g., partial spheres        resulting from crushed bubble shapes or other irregular shapes        that form natural flow channels to facilitate fracture fluid        flow.    -   The mixing efficiency of particles 20 increases with surface        roughness to interact with zero velocity zone or non-slip        polymer surface to promote kinetic friction rather than static        friction.    -   Particles 20 should be sufficiently hard so that the hydraulic        fracturing fluid is deformed around particle 20 to promote        kinetic mixing through the tumbling or rolling effect of        particle 20.    -   Particles 20 should be size proportional to the boundary layer        of the hydraulic fracturing fluid being used so that particles        20 roll or tumble using kinetic rolling friction so that        particles 20 are not drug within the boundary layer of the        fluid. Dragging particles 20 within the boundary layer increases        negative effects of the boundary layer based on increased        surface roughness, thereby restricting flow, or can produce the        removal of particle 20 from the boundary layer of hydraulic        fracturing fluid into the bulk fluid.    -   Particles 20 should be able to reconnect in the boundary layer        of the hydraulic fracturing fluid layer from the bulk fluid        during the mixing process based on particle size and surface        roughness.    -   Particles 20 can be solid or porous materials, manmade or        naturally occurring minerals and or rocks.

Particles 20 for use in the method of the invention must have desirablesurface characteristics. One embodiment of desirable surfacecharacteristics is sharp edges. Sharp edges may be formed on particlesby a jet mill process. During a jet mill process, particles strike eachother to form a sharp edge via a conchoidal fracture. Even though someparticle size selections will produce different effects depending on thefluid selection, it is the edge effect that produces the desiredperformance.

Materials that will produce sharp edge effects upon jet milling include:pumice, Perlite, volcanic glass, sand, flint, slate and granite in avariety of other mineable materials. There are a variety of man-madematerials, such as steel, aluminum, brass, ceramics and recycled and/ornew window glass. These materials can be processed either by jet millingor by other related milling processes to produce a sharp edge with smallparticle sizes. Nano materials are ideally suited for producing kineticboundary layer mixing particles. In addition to the listed examples,other materials may also be suitable, provided the materials havesufficient hardness, estimated to be 2.5 on the Mohs hardness scale.

A variety of materials having a hardness greater than 2.5 will work aslikely candidates to produce sharpened edge effects. These materials,therefore, are likely candidates for the kinetic mixing particlesrelating to the boundary layer. The materials are also likely candidatesfor structural filler to be incorporated in plastics, polymers, paints,adhesives, oils, gases and process fluids. The Mohs hardness scale,showing the hardness of a variety of materials, is presented below:

Hardness Mineral Absolute Hardness 1 Talc (Mg₃Si₄O₁₀(OH)₂) 1 2 Gypsum(CaSO_(4•2)H₂0) 2 3 Calcite (CaCO₃) 9 4 Fluorite (CaF₂) 21 5 Apatite(Cas(PO₄)₃(OH-, C1-, F-) 48 6 Orthoclase Feldspar (KA1Si₃O₈) 72 7 Quartz(SiO₂) 100 8 Topaz (Al₂SiO₄(OH-Y-)₂) 200 9 Corundum (Al₂O₃) 400 10Diamond (C) 1500

The mixing efficiency of a particle is increased when surface dynamiccharacteristics of the particle are increased. Examples of particlesurface dynamic characteristics include characteristics such as sharpbladelike edges as may result from concoidal fractures, smooth surfaces,surface roughness or surface morphology, three-dimensional needlelikeshapes and thin curved surfaces. Increasing surface dynamiccharacteristics has a twofold effect. The first effect is that surfacecharacteristics and particle geometry of a particle having increasedsurface dynamic characteristics enhance surface adhesion to the nonslipzone or the sticky or gluey region of the boundary layer, which producesresistance to particle rolling or tumbling. The second effect ofincreasing surface dynamic characteristics is an increased resistance ofthe ability of the particle to roll and tumble, which results instronger mechanical interaction with the impacting fluid. Therefore, ifthe material dynamic surface characteristics are increased, then dynamicmixing is increased, which increases cohesion forces in the sticky/glueyregion. Increased rotational resistance is then promoted, whichincreases the cutting or chopping effects of sharp bladelike particlesurface features. The ability to grind and cut during particle tumblingor rotation produces kinetic boundary layer mixing.

Images Showing Particles Exhibiting Fracture.

Example materials include ash, expanded perlite, recycled glass thatexhibit conchoidal fractures that produce sharp edges. Other examplematerials include ash, expanded perlite, recycled glass having sharpbladelike edges.

A variety of materials have the ability to fracture. For example,striated or vitreous minerals are not good candidates because theypropagate fractures on striation lines, which limits their ability toproduce sharp bladelike characteristics. As an example, Alternatively,minerals such as flint and obsidian do not fracture along striationlines. As a result, historically these minerals have been useful formaking objects with sharp edges, e.g., arrowheads, spearheads, knivesand even axes.

Other examples include ash, expanded perlite, and recycled glass havingsmooth edges.

A smooth edge on a knife blade lowers the resistance to creating a cutas well as lowering an amount of force required to be applied to theholding device. The same principle is applicable to sharp smooth edgesof particles 20, which allow kinetic mixing to take place while particle20 remains in a boundary layer, tumbling or rolling along the sticky orgluey region. If the surface of particle 20 is sharp and rough, thenresistance due to the surface roughness will be enough to removeparticle 20 from the boundary layer by overcoming cohesive forcesproduced by the sticky or gluey region. Therefore, particles 20 withsharp, smooth, bladelike characteristics can remain in a boundary layerto promote kinetic mixing.

Other examples include ash, expanded perlite, and recycled glass havinga complex surface geometry, such as blade-like characteristics withdynamic curves to promote surface adhesion in the stick or gluey region.

A complex, three-dimensional surface area of a particle is sufficient topromote tumbling or rolling. The above referenced images that show theash and the expanded perlite clearly shows complex surface geometrycharacteristics used for kinetic mixing in the boundary layer.

Other examples include ash, expanded perlite, and recycled glass havingneedle-like points and curves.

Three-dimensional, smooth needle-like tips interact with a boundarylayer by protruding into the moving fluid region adjacent to theboundary layer to promote tumbling or rolling. The smooth needle-likecharacteristics create sufficient fluid force to produce particlerotation while minimizing cohesive forces applied by the deformation offluid flowing around the particle, thereby overcoming aerodynamic liftforces, which are not sufficient to remove the particle from the stickyor gluey region.

Other examples include ash, expanded perlite with surface curves, e.g.,a thin smooth curved particle similar to an egg shell. The surfacecurves allow good adhesion to the sticky layer while promoting dynamiclift on the curved thin particle. The dynamic lift promotes rotation,thereby producing kinetic mixing in the boundary layer. Expanded perlitemay exhibit thin surface curves for producing kinetic mixing in theboundary layer.

Other examples include reactive particle shaping of porous materials,such as unprocessed ash spheres, processed ash, course processedexpanded perlite, and finely processed expanded perlite.

These previously mentioned materials, because of their unique surfacecharacteristics, such as thin curved walls, smooth bladelike shapes andthree-dimensional surface geometry, as well as a Mohs scale hardness ofat least 2.5 have the ability to change their physical particle sizeunder high pressure while maintaining the dynamic surfacecharacteristics discussed above to achieve kinetic boundary layermixing. For example, particles that are too large can be swept off theboundary layer into the main fluid where the particles can undergofracturing produced by high pressure and fluid turbulence, therebyreducing their particle size. Particles having an appropriate size afterfracturing will tend to migrate towards the boundary layer where theparticles will come in contact with the sticky or gluey region topromote kinetic boundary layer mixing. Particle sizing may also takeplace in the boundary layer against mechanical surfaces caused by fluidimpacting pressures. While undergoing fracturing, the thin smooth wallsproduce sharp knifelike blade characteristics regardless of the fracturepoint and regardless of the hardness of the material. This helpsmaintain three-dimensional surface characteristics to promote tumblingor rolling in the boundary layer.

Particle Hardness and Toughness:

Mixing blades and high shear mixing equipment are usually made ofhardened steel. Polymers are softer when mechanical agitation is appliedduring mixing. Since particles added to a polymer pass through theequipment, the particles need to have an ability to retain their shapefor the particles to function properly. Chemical interactions betweenmolecules have been tested and organized based on their hardness. Aminimal hardness of 2.5, starting with copper on the Mohs scale, orharder is sufficient for a single pass particle to be tough enough forthis mixing process.

Additive Loading Suggestions

0.5 percent by formula weight and increase until desired results areachieved or one or more of the expected outcomes are obtained.

Expected Outcomes

When used with plastics, particles of Type I or III resulted indecreased energy use, increased throughput, better surface quality,increased dispersion of additives and an ability to lower processtemperatures and maintain production.

When used with fluid polymers, particles of Type I or III resulted inincreased dispersion times of additives, a decrease in additives needed,decrease in energy uses during agitation, better surface interaction,better mixing between plural component materials.

When used with simple fluids, particles of type I or III resulted inincreased dispersion times of additives, decrease in additives needed,decreased energy uses during agitation, and better surface interaction.

When used with oils, particles of type I or III resulted in an increasein fluid flow, a decrease in viscosity, and in self-cleaning ofmechanical surfaces. The invention relies on the fundamental principleof kinetically moving the boundary layer of a fluid. Particle geometryselection and particle size selection are skills needed by someoneskilled in the art to utilize this technology with a variety offormulations. Therefore, the details related to millions of currentformulations in the chemical and polymer fields will not be fullydiscussed herein. Fluid viscosity is affected by temperature, additives,polymers, chain links, reactions, and mixing, which all directly affectthe boundary layer thickness. The invention relates to a starting pointfor selecting particle characteristics and general fluid selection froma variety of polymers to produce the ability to kinetically move orinteract with the boundary layer.

Thus, the present invention is well adapted to carry out the objectivesand attain the ends and advantages mentioned above as well as thoseinherent therein. While presently preferred embodiments have beendescribed for purposes of this disclosure, numerous changes andmodifications will be apparent to those of ordinary skill in the art.Such changes and modifications are encompassed within the spirit of thisinvention as defined by the claims.

What is claimed is:
 1. A method of increasing flow of drilling fluidsthrough wellbore comprising the steps of: blending a kinetic mixingmaterial with a drilling fluid to form a combined material, wherein saidkinetic mixing material is comprised of particles wherein at least 25%of said particles have a complex three dimensional surface area having asharp surface; pumping said combined material into said wellbore;recycling said combined material through the wellbore wherein saidkinetic mixing material is comprised of perlite.
 2. The method accordingto claim 1 wherein said kinetic mixing material is comprised of:particles having thin walls.
 3. The method according to claim 1 whereinsaid kinetic mixing material is comprised of: particles defining threedimensional blade shapes.
 4. The method according to claim 1 whereinsaid kinetic mixing material is comprised of: particles having slightlycurved thin walls.
 5. The method according to claim 1 wherein saidkinetic mixing material is comprised of: crushed hollow spheres.
 6. Themethod according to claim 1 wherein said kinetic mixing material iscomprised of: particles having corners defined by planes intersecting at90° or less.
 7. The method according to claim 1 wherein said kineticmixing material is comprised of: particles having conglomeratedprotruding arms.
 8. The method according to claim 1 wherein said kineticmixing material is comprised of: semi-spherical material havinghair-like fibers protruding from a surface of said material.
 9. Themethod according to claim 1 wherein said kinetic mixing material iscomprised of: particles having a Mohs hardness value of greater than2.5.
 10. The method according to claim 1 wherein: said complexthree-dimensional surface comprises needle-like shapes.
 11. The methodaccording to claim 1 wherein: said perlite is added to said drillingfluid at percentages from 0.05% to 85% by weight of said blend.
 12. Themethod according to claim 1 wherein: said kinetic mixing material is ina fluidized slurry.
 13. The method according to claim 1 furthercomprising the step of: forming a mixture of said kinetic mixingmaterial and an additive formulation before said step of blending. 14.The method according to claim 13 wherein: said mixture comprises 0.05%to 85% by formula weight of said kinetic mixing material.
 15. The methodaccording to claim 13 wherein: said additive formulation is a polymer.16. The method according to claim 13 wherein: said additive formulationis selected from a group consisting of a cross-linked water based fluid,an oil based fluid, an oil-in-water emulsion, and a foam.
 17. The methodaccording to claim 13 wherein: said step of forming a mixture comprisesintroducing said kinetic mixing material and said additive formulationinto a mixer, wherein said mixer is a turbine blade system or animpeller system.
 18. The method according to claim 13 wherein: said stepof forming a mixture comprises introducing said kinetic mixing materialand said additive formulation into a mixer, wherein said mixer is ashear system.
 19. The method according to claim 18 further comprisingthe steps of: adjusting a size of said kinetic mixing material to form aparticle of a desired size during said step of forming a mixture. 20.The method according to claim 18 wherein: said step of forming a mixturecomprises homogenizing said kinetic mixing material and said additiveformulation to form an emulsion.
 21. The method according to claim 13wherein: said step of forming a mixture comprises introducing saidkinetic mixing material and said additive formulation into a mixer,wherein said mixer is an impingement system.
 22. The method according toclaim 21 further comprising the steps of: adjusting a size of saidkinetic mixing material to form particles of a desired size during saidstep of forming a mixture.
 23. The method according to claim 1 wherein:said step of blending comprises introducing an additive formulation intosaid drilling fluid by mechanical shear.
 24. The method according toclaim 1 wherein said step of blending comprises: introducing an additiveformulation and said drilling fluid into an in-line shear mixing system.25. The method according to claim 24 wherein: said in-line shear mixingsystem includes a recycle loop for recycling said blend through saidin-line shear mixing system until desired dispersion is achieved. 26.The method according to claim 1 wherein: said particles are shaped withprocess pressure.
 27. The method according to claim 1 wherein: saiddrilling fluid is a low viscosity simple drilling fluid.
 28. The methodaccording to claim 27 wherein: said low viscosity simple drilling fluidis water and additives.
 29. The method according to claim 27 wherein:said low viscosity simple drilling fluid is diesel and additives. 30.The method according to claim 1 wherein: said drilling fluid is a highviscosity complex drilling fluid comprising a suspended solids andadditives.
 31. The method according to claim 1 further comprising thestep of: cleaning mechanical surfaces with said particles during saidsteps of pumping and said step of recycling.